Immunoreactivity of valosin-containing protein in sporadic amyotrophic lateral sclerosis and in a case of its novel mutantImmunoreactivity of valosin-containing protein in sporadic amyotrophic lateral sclerosis and in a case of its novel mutant孤発性ALSと新規VCP変異を有するALS-VCPにおけるVCPの免疫組織学的検討